What is pericarditis?Pericarditis is inflammation or infection of the pericardium, the thin sac (membrane) that surrounds the heart. There is a small amount of fluid between the inner and outer layers of the pericardium. When the pericardium becomes inflamed, the
amount of fluid between its two layers increases, compressing the heart and interfering with the heart's ability to function properly.
The heart is surrounded by a flexible two-layered membrane called the pericardium. The two layers are separated by a thin slick of fluid that allows the layers to glide easily over each other. The roles of the pericardium include keeping the heart in place and protecting it from catching secondary infections.
Pericarditis is fairly common. It affects approximately one in 1,000 people. The most common form is caused by infection with a virus. People in their 20s and 30s who have had a recent upper respiratory infection are most likely to be affected, along with men aged 20-50. One out of every four people who have had pericarditis will get it again, but after two years these relapses are less likely.